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Question :
56. If a planet has 3 times the radius of : 2102144

56. If a planet has 3 times the radius of the Earth, but has the same density as the Earth, what is the gravitational acceleration at the surface of the planet? (*g* = 9.8 m/s^{2})

A. 29.4 m/s^{2}

B. 88.2 m/s^{2}

C. 265 m/s^{2}

D. 3.27 m/s^{2}

57. If a planet has a radius 20% greater than that of the Earth but has the same mass as the Earth, what is the acceleration due to gravity at its surface?

A. 14 m/s^{2}

B. 12 m/s^{2}

C. 8.2 m/s^{2}

D. 6.8 m/s^{2}

58. The acceleration due to gravity at the surface of Planet X is 10 m/s^{2}. What is the acceleration due to gravity at an altitude of 3 000 km above the surface of this planet?

A. 10 m/s^{2}

B. 8.0 m/s^{2}

C. 4.4 m/s^{2}

D. More information is needed.

59. An object when orbiting the Earth at a height of three Earth radii from the center of the Earth has a weight of 1.00 N. What is the object's mass? (*g* at the surface of the Earth is 9.8 m/s^{2})

A. 0.102 kg

B. 0.306 kg

C. 0.92 kg

D. 1.0 kg

60. Somewhere between the Earth and the Moon is a point where the gravitational attraction of the Earth is canceled by the gravitational pull of the Moon. The mass of the Moon is 1/81 that of the Earth. How far from the center of the Earth is this point?

A. 8/9 the way to the Moon

B. 9/10 the way to the Moon

C. 3/4 the way to the Moon

D. 80/81 the way to the Moon